sync with overcycler: renamed synth.* -> sh.*
sync with overcycler: renamed p600.* -> synth.*
sync with overcycler: merging changes (fixes & speedups)
sync with overcycler: adding MIDI pitch bend / modwheel support -- less stuff in synth_update()
midi: now sending note on/off, pitchbend, modwheel events on MIDI out
footswitch support: to latch chords in unison and to hold notes while using the arpeggiator
arp: can now be synced by MIDI clock or by pulses on "Cassette in" ("From tape" + 8 to change sync source)